Resolve dialyzer errors

.travis.yml

@@ -1,19 +1,13 @@
 language: elixir
 elixir:
-  - 1.0.3
-  - 1.0.4
+  - 1.1.1
 otp_release:
-  - 17.4
+  - 18.0
 before_script:
-  - export PATH=`pwd`/elixir/bin:$PATH
-  - export PLT_FILENAME=elixir-${TRAVIS_ELIXIR_VERSION}_$TRAVIS_OTP_RELEASE.plt
-  - export PLT_LOCATION=/home/travis/$PLT_FILENAME
-  - wget -O $PLT_LOCATION https://raw.github.com/danielberkompas/travis_elixir_plts/master/$PLT_FILENAME
   - mix local.hex --force
   - mix deps.get --only test
 script:
   - mix test
-  - dialyzer --no_check_plt --plt $PLT_LOCATION -Wno_match -Wno_return --no_native _build/test/lib/ex_twiml/ebin
 after_script:
-- MIX_ENV=docs mix deps.get
-- MIX_ENV=docs mix inch.report
+  - MIX_ENV=docs mix deps.get
+  - MIX_ENV=docs mix inch.report

lib/ex_twiml/reserved_name_error.ex

@@ -17,6 +17,7 @@ defmodule ExTwiml.ReservedNameError do
   defexception [:message]
 
   @doc false
+  @spec exception(list) :: %__MODULE__{}
   def exception([{name, context, _}, file_name]) do
     file_name = Path.relative_to_cwd(file_name)
     name = to_string(name)